No abstract

This study analysed data from a large-scale commercial Up-Country dairy farm, to better understand the impact of lameness on fertility. Over a 12-month period, cattle were locomotion scored five times (every 3 months). Lameness was defined as a locomotion score (LS) of >1 (1-5 scale) and thus included mildly-lame cows. The initial univariate analysis showed that cows which had two LS >1 in the first 180 days after calving and cows which had a LS>1 in the first 90 days after calving had a lower risk of pregnancy and a longer calving-to-conception interval than non-lame (LS=1) counterparts (p=0.019 and p=0.023 respectively). The multivariate model (Cox-proportional hazard model) identified that, although the hazard of pregnancy was still lower in cows with an LS>1 in the first 90 days after calving, the data were compatible with a reduction in the hazard and no effect (HR=0.68; 95% CI: 0.44-1.07). In contrast, cows that had two LS>1 in the first six months after calving (in both the 0-90-and 90-180-day periods) had a clear negative effect on the hazard of pregnancy. The hazard ratio for twice-lame cows in comparison with non-lame counterparts was 0.44 (95%CI 0.23-0.84), and the median calving-to-conception interval was 133 days longer. Although this data was from only one dairy herd, there is strong evidence that even mild lameness is associated with reduced fertility. Further research is needed from more Sri Lankan herds to better understand the impact of lameness on reproductive performance.